title: Determination of methomyl in the stomach contents of baited wildlife by gas chromatography-mass spectrometry.
abstract: The poisoning of wildlife with fly-bait containing the active ingredient methomyl is an intentional and illegal act in many jurisdictions. A case of 2 animals poisoned by methomyl through consumption of tainted bait at multiple stations is described. Although thermally and ultraviolet-labile, methomyl can be identified by gas chromatography-mass spectrometry and is detected in abundance in bait samples; however, it is not readily observed in tissues, owing to its rapid metabolism and elimination. The application of derivatizing functionalities, such as trimethylsilyl groups, stabilizes the methomyl-oxime metabolite to facilitate its detectability during exposure to the relatively harsh conditions of gas chromatography. This brief communication reports on the analytical detection of methomyl in baits and biological samples from poisoned wildlife. Essential to the case were the added determination of a fly-bait coactive ingredient, (Z)-9-tricosene, and identification of a chemical indicator, caffeine, to confirm both the type of pesticide product involved in the poisoning incident and the vehicle used to perpetrate its delivery.
authors.affiliation: 1John P. Buchweitz, Diagnostic Center for Population and Animal Health, Toxicology Section, Michigan State University, 4125 Beaumont Road, F130 Veterinary Medical Center, East Lansing, MI 48910-8104. buchweitzj@dcpah.msu.edu.
authors.forename: John P
authors.initials: JP
authors.lastname: Buchweitz
authors.forename: Mark
authors.initials: M
authors.lastname: Bokhart
authors.forename: Margaret
authors.initials: M
authors.lastname: Johnson
authors.forename: Andreas
authors.initials: A
authors.lastname: Lehner
mesh_terms: D000475:Alkenes / Q000032:analysis*; D000818:Animals; D000835:Animals, Wild / Q000378:metabolism*; D002415:Cats; D008401:Gas Chromatography-Mass Spectrometry / Q000662:veterinary; D005766:Gastrointestinal Contents / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis / Q000378:metabolism* / Q000506:poisoning; D008724:Methomyl / Q000032:analysis / Q000378:metabolism* / Q000506:poisoning; D008824:Michigan; D009893:Opossums
chemical_list: D000475:Alkenes; D007306:Insecticides; D008724:Methomyl; C003646:muscalure
keywords: (Z)-9-tricosene; Caffeine; gas chromatography–mass spectrometry; methomyl